Topic: Figuring out rear master cylinder and spindle

[Dime]

So I am in the process of starting to figure out mounting the rear master cylinder and spindle.

I thought about getting a spindle off a 750f bike but I don't think the shaft of the spindle is long enough.

So what I am thinking now is cutting the shaft of my k one, cutting the shaft off the kz1000 ltd one and putting the shaft on the kz1000 one.

I still don't know how I am going to mount the master cylinder and reservoir.

Was hoping someone might have some experience or ideas.

Attaching a picture of the k spindle on the left and the kz1000 setup on the right.

Thanks in advance

[BenelliSEI]

For inspiration: My Rickman CR has the rear master mounted a long way from the pedal crank. It’s connected with a long threaded rod with a rod end at both ends. Shortening or lengthening the rod allows for pedal location adjustment. Here’s a photo of it all mocked up about a year ago.

[Dime]

For inspiration: My Rickman CR has the rear master mounted a long way from the pedal crank. It’s connected with a long threaded rod with a rod end at both ends. Shortening or lengthening the rod allows for pedal location adjustment. Here’s a photo of it all mocked up about a year ago.

That is quite interesting. Thank you for sharing.

I went ahead and married the two different spindles. I used the k spindle that meets the pedal arm and the kz1000 back half. No idea if I will use this setup but it is a start.

I haven't messed around with rear master cylinders before so I am not clear on their operations. When the pedal is pushed down is the rod on the master cylinder supposed to be pushed towards the master cylinder or pulled away from it?

Right now the setup I have would pull the tod away from the master cylinder not towards.

Total newb when it comes to rear master cylinders. I have done a lot of work on front master cylinders but none on rear.

[BenelliSEI]

That Kawi master in your photo definitely needs a push lever to drive the cylinder into the case. If you look closely at the Rickman Girling master in my photo it has an “L” shaped lever that turns the pull into a push. It’s probably easier to swing your crank 180 degrees on the shaft and turn it into a push?

[Dime]

That Kawi master in your photo definitely needs a push lever to drive the cylinder into the case. If you look closely at the Rickman Girling master in my photo it has an “L” shaped lever that turns the pull into a push. It’s probably easier to swing your crank 180 degrees on the shaft and turn it into a push?

I can turn the spindle 180 degrees to turn it into a push but I will have to eliminate the L bracket on the back of the spindle as it hits the frame. I don't think I even need that braket because the brake light switch is operated of the pedal on my bike and I can't see any need for those two brackets.

[Alan F.]

My first instinct was to look at the parts diagrams for the relavent Kawasaki model, look at the rear master cylinder and look at the brake pedal, that might inspire some ideas.
https://www.partzilla.com/catalog/kawasaki

[Dime]

My first instinct was to look at the parts diagrams for the relavent Kawasaki model, look at the rear master cylinder and look at the brake pedal, that might inspire some ideas.
https://www.partzilla.com/catalog/kawasaki

The orientation of the kz1000 spindle is the same position I can't currently put it in due to the rear brackets. That being said the cb750 uses a sping near the pedal for return and also uses the brake switch off the brake pedal so I don't need the rear bracket on the kz1000 piece.

The master cylinder orientation is as I figured.

Thank you sir

[Dime]

Have removed the back bracket and bent the spindle bracket to give me line of sight to use k brake arm as mockup. Thinking I will make a bracket and mount the master cylinder on the upper frame using the rod as a connector. The clearance is tight so I won't know for sure if I have clearance until I get the shocks in place and figure out swing arm travel.

[Dime]

Proposed master cylinder location

[BenelliSEI]

If there is a bleed screw on the cylinder, get it as high as possible. Looks good.

[Dime]

If there is a bleed screw on the cylinder, get it as high as possible. Looks good.

There is no bleed screw that I can see

[BenelliSEI]

If there is a bleed screw on the cylinder, get it as high as possible. Looks good.

There is no bleed screw that I can see

That usually means you bleed via the caliper bleed screw. Ideally the master should have the outlet hose at the top and the caliper should be higher than that point…… if not you can always hang it a bit lower when bleeding the system, and then mount it back in the ideal location.

[Dime]

If there is a bleed screw on the cylinder, get it as high as possible. Looks good.

There is no bleed screw that I can see

That usually means you bleed via the caliper bleed screw. Ideally the master should have the outlet hose at the top and the caliper should be higher than that point…… if not you can always hang it a bit lower when bleeding the system, and then mount it back in the ideal location.

Ok that makes perfect sense. I just picked up some aluminum flat stock to make the mounts for the master cylinder. I will try to keep it lower than the caliper.

Thank you

[newday777]

I don't think you'll have to have the master lower than the caliper, it isn't on the 78F

[Dime]

I don't think you'll have to have the master lower than the caliper, it isn't on the 78F

Appreciate the picture. It is a little fuzzy but it gives me an idea of what to do with the reservoir. It being lower shouldn't be a problem mounting wise all the same.

[Dime]

So the master cylinder won't be lower than the caliper but I have it mocked up.

The brackets holding it on are aluminum. I wanted something I could bend around the frame.

The side of the master caliper towards the right side of the bike, the bolts holding the bracket to the caliper squeezes the bracket and clamps onto the frame.

This is as far as I got. Ran out of garage time.

[Dime]

Have the reservoir mocked up. I like the location just worried about routing the brake line back to the master cylinder around the shock.

[Dime]

Making some progress. Used the old 750k brake rod as  a rod to the master cylinder. The part I cut off the spindle on the 750k I cut off the small hole, bored it out and welded to the end of the rod to mate up with the master cylinder.

This setup allows full travel of the master cylinder only problem is where the rod attaches to the master cylinder when in operation that joint tends to flex and bind.

So I need to figure out how to immobilize the joint to remove the flex point.

[dusterdude]

I installed a cbr setup on my 750 a few years ago,if i think about it this weekend,ill get pics of it

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[Dime]

I installed a cbr setup on my 750 a few years ago,if i think about it this weekend,ill get pics of it

Sent from my SM-S711U using Tapatalk

Much appreciated.

[Dime]

So I tried to modify the connection I had made on the k8 brake rod. I tried to weld the top of the male end to build it up as to square it off to fit more snugly and lock the connection with the clevis on the master cylinder. Unfortunately as soon as I went to weld it, it melted the male end and ruined it.

So I went online and sourced a threaded clevis, a male end and a piece of m8 x 1.25 threaded rod. Cost me $18 Canadian. This was kinda the route I was headed anyway, I just wanted to see if I could make the stock parts work for mock up.

Canada post is on strike so not sure when I will receive it. Patience is a virtue, LOL